non_constant_identifier_names

The variable name '{0}' isn't a lowerCamelCase identifier.

The analyzer produces this diagnostic when the name of a class member, top-level declaration, variable, parameter, named parameter, or named constructor that isn't declared to be const, doesn't use the lowerCamelCase convention.

The following code produces this diagnostic because the top-level variable Count doesn't start with a lowercase letter:

var Count = 0;

Change the name in the declaration to follow the lowerCamelCase convention:

var count = 0;